<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
    </head>
    <body>
        <h1>My First Web Page</h1>
        <p>My First Paragraph.</p>
        <button onclick="myFunction()">点击这里</button>
        <script>
            function myFunction() {
                document.write("糟糕！文档消失了。");
            }
        </script>
    </body>
</html>